Photovoltaic-thermal synergistic drive fuel cell hybrid power system for improving efficiency and carbon fixation

Abstract

The present invention discloses a photovoltaic-thermal synergistic drive fuel cell hybrid power system for improving efficiency and carbon fixation, which includes an MCFC battery, an SOEC electrolysis cell, a heat release device, an alcohol synthesizer, a photovoltaic power supply device, and a photothermal heating device. The thermal process of the present invention follows the scientific energy utilization principle of "matching temperature and cascaded utilization". The "synergy of solar photovoltaic and thermal energy" develops the characteristics of improving efficiency and carbon fixation of the fuel cell hybrid power system. The newly added heat release device provides high-temperature heat energy for the hydrogenation and alcoholization process of carbon dioxide, the photovoltaic energy provides electricity for the hydrogenation and alcoholization process of carbon dioxide, and the photothermal energy provides low-temperature separation heat energy for the purification process of alcohol substances. The present invention provides a new carbon fixation path for the fuel cell hybrid power system, making it no longer limited to the traditional carbon fixation path of compressed liquefied carbon dioxide, consuming a large amount of renewable energy, achieving carbon fixation without increasing carbon, and the hydrogenation and alcoholization process of carbon dioxide also improves the conventional hybrid power system, increasing efficiency while fixing carbon.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cell hybrid power systems, and more specifically, to a photovoltaic-thermal synergistic drive fuel cell hybrid power system for improving efficiency and carbon fixation. Background Art

[0002] Hydrocarbon fuels have always been one of the important energy sources supporting current social production and life. In the power industry, the main utilization method of hydrocarbon fuels is direct combustion, and the heat released by combustion is converted into electrical energy through a heat engine. However, this energy utilization method has serious irreversible losses at the source, that is, high-grade chemical energy is first converted into medium- and low-grade heat energy, and then further converted from heat to work for power generation, ultimately resulting in limited power generation efficiency of hydrocarbon fuels. Although the technical level of thermal power generation systems has improved in the past few decades, their power generation efficiency is still generally limited between 35% and 55%. In view of this, a fuel cell-based hybrid power system has been proposed to reduce the irreversible loss of direct conversion of chemical energy into heat energy at the source and increase the power generation efficiency of hydrocarbon fuels to more than 60%.

[0003] Although advanced energy systems have achieved an increase in the power generation efficiency of hydrocarbon fuels, in the face of the increasingly prominent carbon emission problem, carbon dioxide capture, utilization, and storage technologies have received extensive attention. Taking the molten carbonate fuel cell hybrid power system as an example, the generated carbon dioxide is separated from the air through the dual reaction processes of the cathode and anode, and the integrated pure oxygen combustion technology realizes carbon dioxide capture. This carbon capture approach is significantly superior to the previous chemical absorption or physical adsorption carbon capture methods with high energy consumption, large equipment, and high costs.

[0004] However, how to deal with the captured carbon dioxide deserves in-depth consideration. Traditional carbon dioxide storage technologies usually involve methods such as high-pressure liquefaction or underground injection. However, these methods not only have technical challenges, such as geological conditions limitations, safety issues, etc., but also often require a large amount of energy and funds during implementation, and at the same time, additional energy consumption during carbon storage also increases the system's carbon emissions. Therefore, regarding carbon dioxide as a raw material and using renewable energy to upgrade and utilize it to produce high-value products is the starting point of the present invention. In addition, while fixing carbon without increasing carbon, the thermal perfection degree of the fuel cell hybrid power system can also be improved, achieving both "fish" (efficiency improvement) and "bear's paw" (carbon fixation) is the originality of the present invention. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and provide a photovoltaic-thermal synergistic drive fuel cell hybrid power system for improving efficiency and carbon fixation.

[0006] To achieve the above object, the present invention provides a photovoltaic-thermal synergistic drive fuel cell hybrid power system for improving efficiency and carbon fixation, including an MCFC battery, an SOEC electrolyzer, a reformer, a post-combustion chamber, a heat release device, a recuperator, a waste heat boiler, a separator, a first compressor, a steam turbine, a second compressor, an alcohol synthesizer, an alcohol rectification column, and a photovoltaic power supply device. The outlet of the reformer is connected to the anode inlet of the MCFC battery. The anode exhaust gas of the MCFC battery is divided into two paths. One path is mixed with fuel and then connected to the inlet of the reformer, and the other path is connected to the inlet of the post-combustion chamber. The outlet of the post-combustion chamber is sequentially connected to the heat release device and the recuperator. The high-temperature exhaust gas of the post-combustion chamber is sequentially passed through the heat release device and the recuperator to release heat and cool down, and then is divided into two parts. One part is mixed with ambient air and oxygen at the anode outlet of the SOEC electrolyzer and then acts as the cathode reaction gas of the MCFC battery after passing through the recuperator. The other part sequentially passes through the waste heat boiler, the separator, and the first compressor. The steam turbine is connected to the waste heat boiler. The extraction outlet in the middle of the cylinder body of the steam turbine extracts steam and passes it into the cathode inlet of the SOEC electrolyzer. The cathode outlet of the SOEC electrolyzer is connected to the inlet of the second compressor. The intermediate extraction outlet of the first compressor and the outlet of the second compressor are respectively connected to the alcohol synthesizer. The outlet of the alcohol synthesizer is connected to an alcohol rectification column. The alcohol rectification column is connected to the solar-thermal heating device. The MCFC battery is connected to the input end of the inverter. The DC output end of the inverter is electrically connected to the SOEC electrolyzer. The photovoltaic power supply device is electrically connected to the SOEC electrolyzer. The heat release device is thermally connected to the body of the SOEC electrolyzer.

[0007] Preferably, ambient air is introduced into the anode of the SOEC electrolyzer as a purge gas. The oxygen discharged from the anode of the SOEC electrolyzer combines with the purge gas to form an oxygen-rich purge gas. The oxygen-rich purge gas is mixed with ambient air and a part of the exhaust gas of the post-combustion chamber and then sequentially enters the recuperator and the cathode of the MCFC battery.

[0008] Preferably, the solar-thermal heating device includes a solar concentrator and a heat storage device. The solar concentrator is connected to the heat storage device. The heat storage device is connected to the alcohol rectification column.

[0009] Preferably, the outlet of the steam turbine is sequentially connected with a condenser and a water pump through a pipeline and finally connected to the inlet of the steam turbine to realize pipeline circulation. A part of the pipeline passes through the waste heat boiler to realize the connection between the steam turbine and the waste heat boiler.

[0010] Preferably, the cathode exhaust gas of the MCFC battery is introduced into the waste heat boiler and then discharged into the environment.

[0011] Preferably, the first compressor is set as an intercooled high-pressure compressor, and the second compressor is set as an intercooled medium-pressure compressor.

[0012] Preferably, the photovoltaic power supply device is a photovoltaic cell.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] 1. The thermal process of the present invention follows the principle of scientific energy utilization. "Solar photovoltaic-thermal synergy" develops the efficiency improvement and carbon fixation characteristics of the fuel cell hybrid power system. Among them, the newly added heat releaser provides the high-temperature heat energy required for the hydrogenation and alcoholization process of carbon dioxide, the photovoltaic power provides the electric power required for the hydrogenation and alcoholization process of carbon dioxide, and the photothermal provides the low-temperature separation heat energy required for the purification process of alcohol substances. The present invention not only provides a new carbon fixation path for the advanced fuel cell hybrid power system, making it no longer limited to the traditional carbon fixation path of compressed and liquefied carbon dioxide, but also consumes a large amount of renewable energy, achieving carbon fixation without increasing carbon. In addition, the hydrogenation and alcoholization process of carbon dioxide also improves the conventional hybrid power system, achieving carbon fixation while increasing efficiency.

[0015] 2. The present invention improves the scientific energy utilization of "temperature matching and cascade utilization" of high-temperature heat energy in the fuel cell hybrid power system. The flue gas temperature of the afterburner in the traditional fuel cell is above 1100°C. In the recuperator, this high-temperature heat energy is often used to heat the reaction gas to about 600°C. The heat transfer temperature difference of >500°C will reduce the energy grade of this heat energy from 0.78 to below 0.66, resulting in serious irreversible losses. The present invention sets a heat releaser at the outlet of the afterburner, and uses the sensible heat of the high-temperature gas section (>800°C) and photovoltaic electric energy to jointly drive the hydrogen production and oxygen production process of the high-temperature solid oxide electrolysis cell, realizing the conversion of high-temperature heat energy into high-grade chemical energy instead of medium-temperature heat energy.

[0016] 3. The power generation performance of the molten carbonate fuel cell of the present invention is improved. The present invention uses air as the purge gas of the solid oxide electrolysis cell. After the purge gas flows through the solid oxide electrolysis cell, it carries part of the heat energy and the oxygen generated by the decomposition of water and mixes with the ambient air. The mixed gas flows through the recuperator and is reheated again. The heated mixed gas is injected into the cathode of the molten carbonate fuel cell. Since the new method injects oxygen-rich air into the cathode of the molten carbonate fuel cell, the cathode gas composition is changed, reducing the cathode resistance loss. At the same time, the heat energy carried by the purge gas of the high-temperature solid oxide electrolysis cell is 100% recycled. Both of them increase the power generation efficiency of the molten carbonate fuel cell itself.

[0017] 4. The exhaust of the low-pressure cylinder of the steam turbine of the present invention provides the required water vapor for the solid oxide electrolytic cell. In the existing technical solutions, the water vapor required for high-temperature water electrolysis to produce hydrogen is often obtained by adding multiple heat exchange surfaces in the waste heat boiler. The working water flows through different heat exchange surfaces to absorb the waste heat of the flue gas and gasify. This technical approach poses challenges to the airflow organization inside the waste heat boiler and the stable operation under variable conditions. The method of the present invention directly extracts the water vapor required for the process of water electrolysis to produce hydrogen from the steam turbine. Since the exhaust technology of the steam turbine is mature, this alternative approach can achieve the source of high-quality water vapor required for water electrolysis to produce hydrogen without modifying the waste heat boiler.

[0018] 5. The thermal perfection of the fuel cell hybrid power system of the present invention is improved. Thanks to the scientific use of high-temperature thermal energy and DC power, the improved power generation performance of molten carbonate fuel cells, and the high system integration, the fuel cell hybrid power system outputs alcohol substances to seal carbon dioxide, while the second law of thermodynamics of the system is improved. Efficiency has been significantly improved.

[0019] 6. The photovoltaic power supply device of the present invention is configured as a photovoltaic cell, and does not require a power storage link. The power supply fluctuation challenge caused by the intermittent distribution of solar energy can be solved through the "DC-DC" conversion and regulation of MCFC cells and inverters to match a stable DC input for the high-temperature hydrogen production process of the SOEC electrolysis cell.

[0020] 7. The outlet of the afterburner of the present invention is newly provided with a heat release device, and the high-temperature waste heat of the exhaust of the afterburner is first utilized at high temperature, and then utilized at low temperature in the regenerator and the waste heat boiler in sequence, thereby achieving temperature matching and step-by-step utilization of thermal energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the structure provided by an embodiment of the present invention;

[0023] Figure 2 It is a schematic diagram of the effect of photovoltaic thermal regulation provided by an embodiment of the present invention;

[0024] Figure 3 The embodiment of the present invention provides Schematic diagram of efficiency effect. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] Please refer to Figure 1 , an embodiment of the present invention provides a photovoltaic-thermal synergistic drive fuel cell hybrid power system for improving efficiency and carbon fixation, including an MCFC battery 2, an SOEC electrolysis cell 11, a reformer 1, a post-combustion chamber 4, a heat release device 5, a recuperator 6, a waste heat boiler 7, a separator 8, a first compressor 9, a steam turbine 10, a second compressor 12, an alcohol synthesizer 13, an alcohol rectification column 14, and a photovoltaic power supply device 17. The structures and working principles of each component will be described below.

[0027] The outlet of the reformer 1 is connected to the anode inlet of the MCFC battery (also known as a molten carbonate fuel cell). The anode exhaust of the MCFC battery 2 is divided into two paths. One path is mixed with the fuel 20 and then connected to the inlet of the reformer 1, and the other path is connected to the inlet of the post-combustion chamber 4.

[0028] Preferably, in this embodiment, the fuel 20 can be selected as methane. One path of the anode exhaust of the MCFC battery is mixed with methane and enters the reformer for reforming reaction, and then is introduced into the anode of the MCFC battery to react with CO3 2- The other path of the anode exhaust enters the post-combustion chamber 4, enabling the unreacted fuel to be further utilized through pure oxygen combustion and releasing high-temperature heat energy. The heat release device 5 is thermally connected to the body of the SOEC electrolysis cell (also known as a solid oxide electrolysis cell). The high-temperature heat energy from the pure oxygen combustion in the post-combustion chamber is transferred to the SOEC electrolysis cell 11 in the heat release device to provide heat energy for electrolyzing water in the electrolysis cell.

[0029] The first compressor 9 is set as an intercooled high-pressure compressor. The outlet of the post-combustion chamber 4 is sequentially connected to the heat release device 5 and the recuperator 6. The high-temperature exhaust gas of the post-combustion chamber 4 is sequentially passed through the heat release device 5 and the recuperator 6 for heat release and temperature reduction, and then is divided into two parts. One part is mixed with ambient air and oxygen at the anode outlet of the SOEC electrolysis cell 11, and after passing through the recuperator 6, it serves as the cathode reaction gas of the MCFC battery 2. Oxygen and carbon dioxide react in the cathode of the MCFC battery 2. The other part sequentially passes through the waste heat boiler 7, the separator 8, and the intercooled high-pressure compressor, thereby realizing the cascaded utilization of the medium-temperature heat energy carried by the gas, as well as the separation and compression liquefaction of carbon dioxide. The cathode outlet of the MCFC battery 2 is connected to the waste heat boiler 7. After the medium-temperature heat energy carried by the cathode exhaust is utilized, the gas is discharged into the environment.

[0030] The steam turbine 10 is connected to the waste heat boiler 7. During specific implementation, the outlet of the steam turbine 10 is successively connected to a condenser 18 and a water pump 19 through pipelines, and finally connected to the inlet of the steam turbine 10, thereby realizing pipeline circulation. A part of the pipeline passes through the waste heat boiler 7 to realize the connection between the steam turbine 10 and the waste heat boiler 7. The high-pressure water in the pipeline absorbs the heat energy in the waste heat boiler 7 and then evaporates and superheats. The superheated steam expands and does work in the steam turbine 10. The exhausted steam after doing work is condensed and replenished with water and then continues to absorb heat in the waste heat boiler. The extraction outlet in the middle position of the low-pressure cylinder body of the steam turbine 10 extracts air and feeds it into the cathode inlet of the SOEC electrolytic cell 11. A part of the steam with a pressure match is extracted from the low-pressure cylinder of the steam turbine and fed into the cathode of the SOEC electrolytic cell to further serve as the reaction gas for solar hydrogen production.

[0031] Among them, the second compressor 12 is set as an intercooled medium-pressure compressor. The cathode outlet of the SOEC electrolytic cell 11 is connected to the inlet of the intercooled medium-pressure compressor. The intermediate extraction outlet of the intercooled high-pressure compressor and the outlet of the intercooled medium-pressure compressor are respectively connected to an alcohol synthesizer 13. The outlet of the alcohol synthesizer 13 is connected to an alcohol rectification column 14. The hydrogen discharged from the cathode of the SOEC electrolytic cell enters the intercooled medium-pressure compressor and is compressed and pressurized.

[0032] The outlet of the intercooled medium-pressure compressor and the intermediate position of the intercooled high-pressure compressor are connected to the alcohol synthesizer 13. Hydrogen and carbon dioxide with a pressure match react in the alcohol synthesizer 13 to produce alcohol substances and water. The produced alcohol substances and water are separated into alcohol and water in the alcohol rectification column.

[0033] Among them, in this embodiment, the solar thermal heating device may include a solar concentrator 16 and a heat accumulator 15. The solar concentrator 16 is connected to the heat accumulator 15, and the heat accumulator 15 is connected to the alcohol rectification column 14. The photovoltaic power supply device 17 is set as a photovoltaic cell.

[0034] The MCFC battery 2 is connected to the input end of the inverter 3 to realize the conversion of direct current into alternating current. The alternating current output from the AC output end of the inverter 3 can be used for external power supply of the system. The DC output end of the inverter 3 is electrically connected to the SOEC electrolytic cell 11. The photovoltaic cell is electrically connected to the SOEC electrolytic cell. The DC output end of the inverter 3 can output part of the direct current to jointly drive the SOEC electrolytic cell 11 to electrolyze water to produce hydrogen and oxygen with the direct current output from the photovoltaic cell. The inverter 3 can output part of the direct current to regulate the fluctuating direct current output from the photovoltaic cell, so as to achieve a material quantity match between the hydrogen production amount of the direct current and the reaction hydrogen amount required for purifying alcohol substances by solar thermal energy.

[0035] After solar energy is incident on the concentrating collector 16 and the photovoltaic cell, the light energy is converted into heat energy and electrical energy. The generated heat energy is stored and released by the heat accumulator 15 to provide the heat energy required for the purification of alcohols for the alcohol distillation column 14. The generated electrical energy is supplied to the SOEC cell 11, and together with the high-temperature heat energy from the heat release device 5, it drives the water decomposition process for hydrogen and oxygen production inside the SOEC electrolytic cell 11.

[0036] Of course, the inverter in this embodiment can adopt an inverter on the market that can output partial direct current.

[0037] The present invention proposes a system variable irradiance operation strategy for regulating a photovoltaic cell with direct current from a molten carbonate fuel cell. The solar irradiance resource has the characteristics of uneven spatial and temporal distribution, resulting in fluctuations in the electrical energy output by the photovoltaic cell. Most existing technical solutions use energy storage devices to balance the instability of photovoltaic electrical energy, but the energy storage devices face challenges such as high costs and low safety and reliability. The present invention explores the potential of the thermal system itself and proposes an operation strategy in which the molten carbonate fuel cell outputs direct current to match the photovoltaic electrical energy in real time. While removing the energy storage device, it cooperates with the heat accumulator to store and release and regulate the concentrating collector, realizing the energy matching between solar photovoltaic and solar thermal in the improvement of the thermal system's efficiency and carbon fixation. The schematic diagram of the effect data is as Figure 2 shown.

[0038] Preferably, ambient air can be introduced into the anode of the SOEC electrolytic cell 11 as a purge gas. The oxygen discharged from the anode of the SOEC electrolytic cell 11 combines with the purge gas to form an oxygen-rich purge gas. The oxygen-rich purge gas is mixed with ambient air and a part of the exhaust gas from the afterburner 4 and then enters the recuperator 6 and the cathode of the MCFC cell 2 in sequence. The present invention uses air as the purge gas for the SOEC electrolytic cell 11. After the purge gas flows through the SOEC electrolytic cell 11, it carries part of the heat energy and the oxygen generated by water decomposition and mixes with ambient air. The mixed gas flows through the recuperator 6 and is reheated again. The heated mixed gas is injected into the cathode of the MCFC cell 2. Since the new method injects oxygen-rich air into the cathode of the MCFC cell 2, it changes the cathode gas composition, reduces the cathode resistance loss, and at the same time, the heat energy carried by the purge gas of the high-temperature SOEC electrolytic cell 11 is recycled 100%. Both of these increase the power generation efficiency of the MCFC cell 2.

[0039] The thermodynamic perfection degree of the fuel cell hybrid power system of the present invention is improved. Thanks to the scientific use of high-temperature heat energy and direct current electrical energy, the improvement of the power generation performance of the molten carbonate fuel cell, and the high system integration, etc., while the fuel cell hybrid power system outputs alcohols to sequester carbon dioxide, the efficiency at the level of the second law of thermodynamics of the system is significantly improved. The schematic diagram of the effect data is as Figure 3 shown.

[0040] In summary, the present invention has the following advantages:

[0041] 1. The thermal process of the present invention follows the principle of scientific energy utilization. "Solar photovoltaic-thermal synergy" develops the characteristics of improving efficiency and carbon fixation of the fuel cell hybrid power system. Among them, the newly added heat releaser provides the high-temperature heat energy required for the hydrogenation and alcoholization process of carbon dioxide, the photovoltaic provides the electric power required for the hydrogenation and alcoholization process of carbon dioxide, and the solar thermal provides the low-temperature separation heat energy required for the purification process of alcohol substances. The present invention not only provides a new carbon fixation path for the advanced fuel cell hybrid power system, making it no longer limited to the traditional carbon fixation path of compressed and liquefied carbon dioxide, but also consumes a large amount of renewable energy, achieving carbon fixation without increasing carbon. In addition, the hydrogenation and alcoholization process of carbon dioxide also improves the conventional hybrid power system, achieving carbon fixation and increasing efficiency at the same time.

[0042] 2. The present invention improves the scientific energy utilization of "temperature matching and cascade utilization" of high-temperature heat energy in the fuel cell hybrid power system. The flue gas temperature of the afterburner in the traditional fuel cell is above 1100 °C. In the recuperator, this high-temperature heat energy is often used to heat the reaction gas to about 600 °C. The heat transfer temperature difference of >500 °C will reduce the energy grade of this heat energy from 0.78 to below 0.66, resulting in serious irreversible losses. The present invention sets a heat releaser at the outlet of the afterburner, and uses the sensible heat of the high-temperature gas section (>800 °C) and photovoltaic electric energy to jointly drive the hydrogen production and oxygen production process of the high-temperature solid oxide electrolysis cell, realizing the conversion of high-temperature heat energy into high-grade chemical energy instead of medium-temperature heat energy.

[0043] 3. The power generation performance of the molten carbonate fuel cell of the present invention is improved. The present invention uses air as the purge gas of the solid oxide electrolysis cell. After the purge gas flows through the solid oxide electrolysis cell, it carries part of the heat energy and the oxygen generated by the decomposition of water and mixes with the ambient air. The mixed gas flows through the recuperator and is reheated again. The heated mixed gas is injected into the cathode of the molten carbonate fuel cell. Since the new method injects oxygen-rich air into the cathode of the molten carbonate fuel cell, it changes the cathode gas composition, reduces the cathode resistance loss, and at the same time, the heat energy carried by the purge gas of the high-temperature solid oxide electrolysis cell is 100% recycled. Both of them increase the power generation efficiency of the molten carbonate fuel cell itself.

[0044] 4. The extraction steam from the low-pressure cylinder of the steam turbine of the present invention provides the water vapor required for the solid oxide electrolysis cell. In the existing technical solution, the water vapor required for high-temperature electrolytic water hydrogen production often passes through adding multiple heat transfer surfaces in the waste heat boiler, and the working medium water flows through different heat transfer surfaces to absorb the waste heat of the flue gas and gasify. This technical approach poses challenges to the gas flow organization and stable operation under variable working conditions inside the waste heat boiler. The method of the present invention directly extracts the water vapor required for the electrolytic water hydrogen production process from the steam turbine. Since the extraction technology of the steam turbine is mature, this alternative approach can achieve the source of high-quality water vapor required for electrolytic water hydrogen production without modifying the waste heat boiler.

[0045] 5. The thermal perfection of the fuel cell hybrid power system of the present invention is improved. Thanks to the scientific use of high-temperature thermal energy and DC power, the improved power generation performance of molten carbonate fuel cells, and the high system integration, the fuel cell hybrid power system outputs alcohol substances to seal carbon dioxide, while the second law of thermodynamics of the system is improved. Efficiency has been significantly improved.

[0046] 6. The photovoltaic power supply device of the present invention is configured as a photovoltaic cell, and does not require a power storage link. The power supply fluctuation challenge caused by the intermittent distribution of solar energy can be solved through the "DC-DC" conversion and regulation of MCFC cells and inverters to match a stable DC input for the high-temperature hydrogen production process of the SOEC electrolysis cell.

[0047] 7. The outlet of the afterburner of the present invention is newly provided with a heat release device, and the high-temperature waste heat of the exhaust of the afterburner is first utilized at high temperature, and then utilized at low temperature in the regenerator and the waste heat boiler in sequence, thereby achieving temperature matching and step-by-step utilization of thermal energy.

[0048] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A photovoltaic-thermal synergistically driven fuel cell hybrid power system for improving carbon fixation efficiency, characterized by: The invention comprises an MCFC cell (2), an SOEC electrolytic cell (11), a reformer (1), an afterburner (4), a heat release device (5), a regenerator (6), a waste heat boiler (7), a separator (8), a first compressor (9), a steam turbine (10), a second compressor (12), an alcohol synthesizer (13), an alcohol distillation tower (14) and a photovoltaic power supply device (17), wherein the outlet of the reformer (1) is connected to the anode inlet of the MCFC cell (2), and the anode of the MCFC cell (2) is connected to the anode of the MCFC cell (2). The exhaust gas is divided into two paths, one of which is mixed with the fuel (20) and then connected to the inlet of the reformer (1), and the other is connected to the inlet of the afterburner (4). The outlet of the afterburner (4) is connected to the heat release device (5) and the regenerator (6) in sequence. The high-temperature exhaust gas of the afterburner (4) passes through the heat release device (5) and the regenerator (6) in sequence to release heat and cool down, and then is divided into two parts. One part is mixed with the ambient air and the oxygen at the anode outlet of the SOEC electrolytic cell (11) and passes through the regenerator (6) to serve as the cathode reactor of the MCFC cell (2). The other part passes through the waste heat boiler (7), the separator (8) and the first compressor (9) in sequence. The steam turbine (10) is connected to the waste heat boiler (7). The exhaust outlet at the middle of the cylinder of the steam turbine (10) exhausts gas into the cathode inlet of the SOEC electrolytic cell (11). The cathode outlet of the SOEC electrolytic cell (11) is connected to the inlet of the second compressor (12). The middle exhaust outlet of the first compressor (9) and the outlet of the second compressor (12) are respectively connected to the alcohol synthesis The alcohol synthesizer (13) is connected to an alcohol distillation tower (14) at its outlet, the alcohol distillation tower (14) is connected to a photothermal heating device, the MCFC cell (2) is connected to an input end of an inverter (3), the DC output end of the inverter (3) is electrically connected to a SOEC electrolysis cell (11), the photovoltaic power supply device (17) is electrically connected to the SOEC electrolysis cell (11), and the heat release device (5) is connected to the body of the SOEC electrolysis cell (11) for heat transfer.

2. The photovoltaic-thermal synergistically driven fuel cell hybrid power system for improving carbon fixation efficiency according to claim 1 is characterized by: Ambient air is introduced into the anode of the SOEC electrolysis cell (11) as a purge gas, and the oxygen discharged from the anode of the SOEC electrolysis cell (11) is combined with the purge gas to form an oxygen-rich purge gas. The oxygen-rich purge gas is mixed with ambient air and part of the exhaust gas from the afterburner (4) and enters the regenerator (6) and the cathode of the MCFC cell (2) in sequence.

3. The photovoltaic-thermal synergistically driven fuel cell hybrid power system for improving carbon fixation efficiency according to claim 1 is characterized by: The photothermal heating device comprises a solar concentrator (16) and a heat accumulator (15), wherein the solar concentrator (16) is connected to the heat accumulator (15), and the heat accumulator (15) is connected to an alcohol distillation tower (14).

4. The photovoltaic-thermal synergistically driven fuel cell hybrid power system for improving carbon fixation efficiency according to claim 1 is characterized in that: The outlet of the steam turbine (10) is connected to a condenser (18) and a water pump (19) in sequence through pipelines, and is finally connected to the inlet of the steam turbine (10), thereby realizing pipeline circulation. A part of the pipeline passes through the waste heat boiler (7), thereby realizing the connection between the steam turbine (10) and the waste heat boiler (7).

5. The photovoltaic-thermal synergistically driven fuel cell hybrid power system for improving carbon fixation efficiency according to claim 1 is characterized by: The cathode exhaust gas of the MCFC cell (2) is introduced into the waste heat boiler (7) and then discharged into the environment.

6. The photovoltaic-thermal synergistically driven fuel cell hybrid power system for improving carbon fixation efficiency according to claim 1 is characterized by: The first compressor (9) is configured as an indirect-cooling high-pressure compressor, and the second compressor (12) is configured as an indirect-cooling medium-pressure compressor.

7. The photovoltaic-thermal synergistically driven fuel cell hybrid power system for improving carbon fixation efficiency according to claim 1 is characterized by: The photovoltaic power supply device (17) is configured as a photovoltaic cell.

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